Crankshaft 61 conrod 107

[Maciej]

hi mates,

I bought 61mm old Cosa crankshaft with 107 conrod. the plan was to use it on with RT225 BGM kit. However I heard that 61mm with 107 conrod is very hard to set correct timings on. What do you think, please advice do I need to change to 110 conrod? Or should try as is?

[Knowledge]

Sometimes, short rods on piston ported barrels can lead to excessive inlet timing, but the best way to check is to dry build the engine and measure the port timings. I am sure that your combination of stroke, rod and kit are uncommon, so it would take a clever person who was familiar with the RT kit and a slide rule to give you an answer without some port timings to work with.

Might I suggest you try the dry build this weekend and report back......?

[Architecten]

MB recommend a 110 conrod...

[Maciej]

Hi, thanks everyone for suggestions. I'll go for 60/110 instead 61/107. If will have some time this week will try dry built and let you know how it looks.